Concrete blocks have been used for many years to construct retaining walls. In recent years, concrete retaining wall blocks are typically dry stacked in ascending courses without the use of mortar to secure the blocks to one another. These “segmental retaining walls” are typically built so that the face of the wall recedes from a vertical plane as the wall ascends. This receding slope of the wall is referred to as “batter”.
Batter is typically specified in terms of degrees from vertical. The larger the batter, the less horizontal pressure that is applied by the soil behind the wall, and the center of gravity is further behind the wall. Both of these factors make the wall less likely to be pushed over by both the soil behind the wall and any hydrostatic pressure that builds up in the soil behind the wall. However, the larger the batter, the larger the amount of space the wall occupies laterally on the earth's surface, and, particularly in cities, that space is often limited.
It is possible to build a wall with batter by preparing the foundation of the wall at the desired angle, and then building up the successive courses with the bottom of the blocks parallel to the initially established angle. It is easier, and more typical, however, to build a perfectly level foundation and then to build up the successive courses so that each course is set back a uniform distance with respect to the course below.
To this end, modern concrete retaining wall blocks are provided with some form of “locator” mechanism that establishes the uniform setback and batter. The locator mechanism generally takes the form of a forward-facing locating surface and a rearward-facing locating surface. Each surface is typically formed on a single block, but, when a plurality of similar blocks are laid in successive courses, the forward-facing locating surfaces of the blocks in one course interact with the rearward-facing locating surfaces of an adjacent course to establish the setback. Examples of such a mechanism are the rear lip (flange) system shown in U.S. Pat. No. 5,827,015, the tongue and groove system shown in U.S. Pat. No. 4,490,075, and the inset wall system shown in U.S. Pat. No. 5,795,105.
In connection with any of the exemplified systems, and other similar systems, the setback and resulting batter of the wall are determined by the relative positions and/or dimensions of the locating surfaces. These relative positions/dimensions are fairly easy to adjust to the desired setback/batter, but must be established at the time of manufacture of the block. It is thus possible for a manufacturer to make a large inventory of blocks of one setback/batter, and to make a second inventory of nearly identical blocks of a second setback/batter. Without careful examination and measurement, it is not easy to tell the blocks that will make a wall with a seven degree batter from the blocks that will make a wall with a four degree batter.
Accordingly, there is a need for a simple means by which one can more readily determine by looking at a retaining wall block what the resulting batter will be from constructing a retaining wall of a multiplicity of the blocks.